Laparoscopic surgery (laparoscopy) is becoming a preferred method for performing various types of surgical opertions, particularly gynecological operations. However, unlike other types of surgical procedures, laparoscopic surgery does not require large incisions to expose the internal organs. Instead, a small hole is cut through the body wall and a laparoscope is inserted therethrough so that the surgeon can visualize the internal organs without the added trauma of a large incision. Various types of surgical instruments are also passed through these types of small holes so that the surgery can be performed while the organs are being visualized through the laparoscope. Thus, the surgery can be performed with a very small incision or hole through the body cavity which is about the diameter of the narrow instruments which are used during the surgical operation.
The instruments are not inserted directly through the hole in the body cavity. Instead, a tubular sheath or cannula is inserted through the hole and the instruments are passed through the opening in the sheath or cannula. Means may be provided for restraining the movement of the laparoscope within the cannula to minimize excessive movement of the laparoscope through the cannula. However, this does not prevent excessive movement of the cannula itself. Thus, the cannula may move up or down through the incision as the surgeon carries out the operation.
Movement of the cannula or sheath will cause undesirable movement of the laparoscope and this movement may distract the surgeon and interfere with the operation. Therefore, it is desirable to minimize the unwanted movement of the cannula. It is also desirable to restrict this unwanted movement of the cannula while allowing the surgeon to reposition the cannula as needed and to alter the angle of the cannula with respect to the patient's body without causing any unwanted up and down movement.
Various types of devices are available for restraining the movement of a cannula which passes into a patient's body. However, none of these devices are designed to overcome the unique problems associated with the requirements of laparoscopic surgery. For example, laparoscopic surgery requires distension of the body cavity by filling it with a fluid, especially CO.sub.2 gas, under pressure, so that the instruments can be safely inserted and the organs can be visualized and manipulated during the operation.
Typically, devices which are designed to restrain or immobilize a cannula, have a clip or similar restraining means on an adhesive disk or pad which is adhered to the patient's skin at the point where the cannula enters the body. However, none of these devices are suitable for laparoscopic surgical procedures because of certain problems associated with the pressurized gas or other fluid in the body cavity. In particular, the pressurized CO.sub.2 gas or fluid tends to be forced out through the incision and this leakage interferes with the adhesive which helps hold the cannula in place. Failure of the adhesive renders a restraining device useless once it becomes separated from the patient's skin. Furthermore, the amount of leakage increases once the cannula is no longer restrained by the adhesive pad over the incision. In addition, CO.sub.2 gas tends to leak between the sheath and the laparoscopic device inserted therethrough.
Another problem associated with other types of prior art cannula stabilizers is that they are designed for use with cannulas which would not be suitable for use in a laparoscopic procedure. For example, cannulas which are in the form of thin flexible infusion or drainage tubes, would not be suitable in a laparoscopic procedure. Cannulas for use in a laparoscopic procedure are generally rigid and of a suitable diameter and length to accommodate the laparoscopic instrumentation. Therefore, the cannulas which are suitable for laparoscopic procedures cannot be bent around clips and similar devices since such bending and the like would make it impossible to insert the laparoscopic instrumentation into the body cavity.
One device for stabilizing the sheath of an endoscope is described in U.S. Pat. No. 4,593,681. The device includes a flexible plastic plate with a central hole through which the sheath of an endoscope passes. The hole is of a predetermined diameter to provide an interference fit with the sheath of a scope inserted therein. An adhesive is provided underneath the flexible plate to adhere the device on a person's body. However, no means is provided to lessen the strain on the adhesive due to the force of the fluid in the body cavity which tends to leak out during the procedure. In addition, this device requires a complex mechanism of moving parts to immobilize the sheath once it has been inserted within the central hole of the device. Furthermore, it is difficult to insert the cannula through the central hole of this device since no means is provided to enlarge the hole or otherwise open it up for easy passage of the cannula therethrough.
During a laparoscopic procedure, it is sometimes desirable to change the angle at which the cannula enters the body cavity in order to view different portions of the internal organs. However, this can place excessive stress on the adhesive and cause it to separate. Thus, it would be desirable to enhance the flexibility of a cannula restraining device so that the angle can be changed with a minimum of stress on the adhesive.
In view of the unique problems associated with stabilizing or immobilizing devices for use with laparoscopic instrumentation and the failure of others to solve these problems, it is clear that a long-felt need exists in the art to provide a device which can easily stabilize a laparoscopic cannula while avoiding the problems caused by the pressurized gas in the patient's body cavity.